Living in an artificial environment without access to the natural solar light, has a strong influence on the circadian clock of humans. Light is the most powerful synchroniser of human internal biological clock. The environmental conditions, however, are different in an extraterrestrial environment, such as in low Earth orbit, deep-space or on other planets. The exposure to the sunlight in space is influenced by the specific location of the habitat in relation to the Sun, as well as by specific habitat system, determining the amount of the crew’s exposure to radiation. Therefore, disruptions in sleep-wake cycles have been common among astronauts. In addition, the lack of sunlight is known to induce Seasonal Affective Disorder (SAD), manifesting through fatigue, concentration and memory problems, decreased mood and obesity. In this paper we discuss the importance of considering time in architectural design as the crucial element to recover natural environment conditions in isolated interior spaces. We propose generic architectural tools for an artificial environment in order to influence an astronaut’s perception of time. To regulate the biological clock of an astronaut, a specific lighting system for isolated environments is introduced. The projected simulation will be looped in a 24-h period, in order to regulate astronaut’s circadian rhythm and create straightforward reference of the time of day. The light will be installed and tested in the M.A.R.S. analogue habitat in Poland.